The present invention relates to a liquid crystal display device, and in particular, relates to a liquid crystal display device with a touch detection function capable of detecting an external proximity object.
In recent years, a touch detection device referred to as a touch panel capable of detecting an external proximity object has attracted attention. The touch panel is mounted on or integrated with a display device such as a liquid crystal display device. In a liquid crystal display device in which a touch panel is mounted on or integrated with a display device, that is, a liquid crystal display device with a touch detection function, various button images or the like are displayed on the display device, and proximity of an external object to a button image is detected through the touch panel. This enables the use of the touch panel as information input means instead of a normal mechanical button. Since such a liquid crystal display device with a touch detection function does not necessarily need information input means such as a keyboard or a mouse, its use tends to increase with the inclusion of mobile information terminals such as mobile phones in addition to computers.
As a detection method of a touch detection device, some methods such as an optical type, a resistance type and a capacitance type are known. Among these types, a capacitance type touch detection device has a relatively simple structure and consumes less power and so is used for mobile information terminals and the like. Japanese Patent Application Laid-Open Publication No. 2012-230657 (Patent Document 1) describes a capacitance type touch detection device.
Further, in the liquid crystal display device, a narrower edge frame has been more and more demanded. Namely, the reduction in width of the edge frame surrounding a display surface of the liquid crystal display device has been demanded.